Samples are loaded and AUC has reached temperatureequilibration.

Open a new file.

Check velocity andinterference for all cells, choose rotor, set speed, time (hold)and temperature.

set scan options set scan method. Here is 1 min between scans

Start the AUC and bring up to the desired speed.

save scan file

0 hrs 1 min 0 sec

Details window for cell# 4.

Laser set up window forcell # 4.

Set zoom to 50% and move sliding bar to right side to visualize the entire fringe pattern.

Next, we have to adjust the Laser Delay.

By re-setting zoom, we can now see the top, meniscus and bottom of the cell

Top (inside) Meniscus Bottom (outside)

Setting the laser delay aligns the laser beam so that it falls exactly down through the center of the center piece sector.

First, on the laser delay bar, left click on the right arrow box to movethe laser.

As the laser moves out of alignment, the right end of the fringe pattern begins to darken.When it looks like the fringe pattern example below, stop and then, using the left arrow box, count each left click of the mouse (1 click =.1degree) as you move the laser back through the middle and out of alignment in the other direction. Again, the right fringe pattern darkens as below. Then, to bring the laser to mid-line, left click on the right arrow box and move the laser back one-half the counted distance.

Laser out of alignment at72.6 degrees.

Laser out of alignment at71.2degrees.

Laser is centered at 71.9.

Now, duration, brightness and contrast need to be adjusted

For a starting point, set Laser duration to .2,bring down the brightness to 22 andset the contrast softer to 107

To finish, bring down the contrast to100 and increase brightness to 26.

Keep fringes and spaces so they are not too dark, and not too white so that you don’tsaturate the bright and dark range of the camera.

Too bright. Too much white space between fringes

Not bright enough and too much contrast. The black areas are too dark.

Too bright and not enough contrast. The black areas are not dark enough.

To set Inside radius, place pointer just before the meniscus and double left clickwith mouse.

To set Outside radius, placepointer at right edge anddouble left click with mouse.

To begin radial calibration for IF scans, from the Interference top menu, open RadialCalaibration.

This window opens. Hit the LaserSetup button.

This window appears. Make sureCell # 8 is checked. We calibrate the laser using the counterbalance. Note Fringe pattern above.

Fringe pattern of a counter balance.

hole in counter balance solid area opposite holeair vs air no transmitted light air vs air

A gray area appears as the border between the counter balance hole and the solidpart.

Adjust Laser Delay as before, by movinglaser out of alignment.

Laser out of alignment again.

Fringes are adjusted for laser delay, duration, brightness and contrast.

To set inside radius, left click on theborder between air and gray space.

To set outside radius, left click on theborder between air and gray space.